Raspberry Pi Mega-IO Expansion Card

This project started with the challenge to integrate as many Home Automation functions as possible into a Raspberry Pi platform.

Two of the Raspberry Pi’s GPIO pins are used for I2C communication. Another pin is allocated for the interrupt handler, leaving 23 GPIO pins available for the user. MEGA-IO adds the following I/O functions:

Eight on-board relays

Eight 12-bit ADC channels

One 12-bit DAC output

Eight opto-isolated inputs

Four open collector outputs

Six GPIO's

Four layer stackable

Configurable interrupts

The Mega-IO card requires +5V power, supplied either from the Raspberry Pi expansion bus, or from its own 2.1mm power jack. The on-board relays are connected to the +5V. A local 3.3V regulator powers the rest of the circuits.

The Mega-IO can be controlled by the a command line utility or by using the drag and drop visual tool Node-Red